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Senin, 04 Agustus 2014

NASA Validates 'Physics Defying' Space Drive

To the surprise of many, a radical new type of spacecraft propulsion system appears to actually work.

NASA recently tested an experimental microwave thruster for a radical new type of spacecraft propulsion system—and to the surprise of researchers, the "physics-defying," fuel-less space drive appears to actually work.

Fuel takes up an enormous amount of space and weighs down current spacecraft, so it would be a tremendous breakthrough to essentially eliminate the need for it, as the "EmDrive" promises to do.

The drive generates thrust by "bouncing microwaves around in closed container" without any need for propellant,according to Wired UK, which has been following the work of its inventor for several years.

That would be Roger Shawyer, a British scientist who in 2001 formed a company called SPR to promote his EmDrive, though to little avail in the face of critics who "reject[ed] his relativity-based theory and insist[ed] that, according to the law of conservation of momentum, it cannot work."

Until recently that is.

Chinese Academy of Sciences researchers built and tested an EmDrive a couple of years ago, reporting in November 2012 that they had achieved success with the experiment.

"At an input power of 2.5kW, their 2.45GHz EmDrive thruster provides 720mN of thrust," Shawyer's SPR site noted. Those numbers meant propulsion delivered by an EmDrive could be "enough for a practical satellite thruster," Wired noted.

Such a drive would still need a power input, but the thrusters "could be powered by solar electricity, eliminating the need for the supply of propellant that occupies up to half the launch mass of many satellites," the tech site said.

Now a second EmDrive-like thruster has been built by U.S. scientist Guido Fetta, who recently worked with a five-person NASA research team at the Johnson Space Center in Houston to test it. Like the Chinese effort, Fetta's "Cannae Drive" actually works "in spite of the law of conservation of momentum," Wired said.

"The torsion balance they used to test the thrust was sensitive enough to detect a thrust of less than ten micronewtons, but the drive actually produced 30 to 50 micronewtons—less than a thousandth of the Chinese results, but emphatically a positive result," according to the site, which reviewed a paper presented by the NASA team at last week's 50th Joint Propulsion Conference in Cleveland, Ohio.

For now, EmDrives and Cannae Drives are clearly still in the experimental stages. There's certainly a big question to be answered about how the Chinese researchers were supposedly able to create a practical thruster while Fetta's effort would need to be vastly improved to ever actually move a spacecraft around.

But for a space community looking at everything from solar sails to ion drives as a means to travel more efficiently between the planets—as well as for potential asteroid deflection missions —another innovative propulsion system is likely to get a long, studious look.

read more : http://www.pcmag.com/article2/0,2817,2461815,00.asp

Rabu, 09 Juli 2014

Sun sends more 'tsunami waves' to Voyager 1

(Phys.org) —NASA's Voyager 1 spacecraft has experienced a new "tsunami wave" from the sun as it sails through interstellar space. Such waves are what led scientists to the conclusion, in the fall of 2013, that Voyager had indeed left our sun's bubble, entering a new frontier.

Read more at: http://phys.org/news/2014-07-sun-tsunami-voyager.html#jCp

Toward quantum technologies

Toward quantum technologies

Quantum mechanics is about to fundamentally change the way we can transmit and sense information. The idea is that information—represented by physical quantities such as the spin or the polarisation of an individual photon—can be transmitted with the help of so-called quantum entanglement. The EU project Q-ESSENCE, completed in April 2013, dealt with the development of new communication and sensing technologies based on quantum mechanical principles. Here, project scientist Martin Plenio, director of the institute of theoretical physics and head of the controlled quantum dynamics group at Ulm University, Germany, talks to youris.com about the challenges and applications of quantum mechanics-based communication technologies and what happened since the completion of the project.Read more at: http://phys.org/news/2014-06-quantum-technologies.html#jCp

Remote quantum applications, teleportation enabled by calling long distance between superconducting qubits

Remote quantum applications, teleportation enabled by calling long distance between superconducting qubits

Schematic of the superconducting optical interface
(Phys.org) —Researchers have developed a way for superconducting quantum chips to talk to each other over large distances through an optical fibre, allowing quantum entanglement or teleportation - both key steps towards building a truly global quantum internet via a quantum repeater.
Devised by Dr Keyu Xia and Professor Jason Twamley from the ARC Centre of Excellence for Engineered Quantum Systems (EQUS) at Macquarie University, and Dr Michael Vanner at the University of Queensland, their idea makes use of the tiny magnetic fields generated by these quantum chips to alter the properties of an optical cavity, via a magnetostrictive material.
A material that is "magnetostrictive" physically expands in the presence of a . By using this, the team were able to show how the magnetic fields from the quantum chips can effectively speak via the  and connected optical fibre through to a distant superconducting chip in another lab elsewhere. "Quantum cryptography, the secret transfer of information over  that is protected via the laws of quantum mechanics, is one application of quantum science and technology that already has commercial applications," said researcher Professor Twamley.
"This and other applications, such as , quantum teleportation and quantum sensing, would benefit greatly from the ability to connect up quantum devices over long distance, for example, if they could plug in to a .
"Superconducting quantum chips are one of the most promising areas of development to become the hardware for tomorrow's quantum computers, and our superconducting/optical interface will help plug these chips together over large distances."
"Our hybrid-quantum system approach allows us to take advantage of both the power of quantum computing with superconducting circuits and existing low-loss
high-speed optical telecommunications technology," said Dr Vanner.
"It's a very exciting direction, quantum technology certainly has a bright future," said Dr Xia.
More information: The full paper "An opto-magneto-mechanical quantum interface between distant superconducting qubits" has been published in the journal Scientific Reportswww.nature.com/srep/2014/14070… 05571/full/srep05571
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